[frankiedon53]

Can mal-function of the RWALsystem cause front caliper brake drag.In diagnosing front brake drag one needs to know this.

[TxGreaseMonkey]

I would say no. Focus on removing, cleaning, and lubricating the front caliper pins with silicone grease. If the problem persists, there's likely a problem with the caliper, where the square-cut seal is not able to retract the piston. Corrosion is the culprit, in these situations, and you need to replace the caliper.

[frankiedon53]

I was thinking about that myself but the calipers are new and came fully loaded.Kelsey/Hayes sliding calipers. Tonight I pedal bled the brakes again front and rear and a peculiar thing happened: After I closed the bleed valve and my assistant was moving her foot of the pedal,for one brief second or two the caliper freed up and the rotor spun freely but then when the pedal was completely released it locked up again even tighter than before. I may not have mentioned that the booster the master cyl. Brake hoses combination valve and calipers were all replaced but it seems as if something could still be wrong with one of them. I appreciate any thoughts that can help.

[TxGreaseMonkey]

I never assume new caliper pins are properly greased--I check them myself. Did you properly adjust the master cylinder pushrod? Did you properly adjust the brake pedal height/brake pedal free play? This could be the problem.

[frankiedon53]

I greased the caliper pins but I was not aware at the time of silicone grease so I used high temperature bearing grease.I intend to change it as soon as I can buy some.Yes I thought the new booster came with the push-rod adjusted but I figured it would'nt hurt to make it a little shorter just to be sure it was'nt pushing on the master too hard.The pedal clearance seem to be right as far as I can tell but there's really no way to adjust it except for bending the part that pushes the brake switch unless of course I'm not understanding something.I looked at again today and I don't see where it can be adjusted.However I'll look again.What do you think about the reconditioned parts.Is it possible that the calipers or the master could be defective.I mean how often does it happen that new or reconditioned parts could be defective? Thanks for your prompt response.

[TxGreaseMonkey]

Use brake cleaner to remove all of the high temp. bearing grease and recoat with silicone grease. See if you can get your hands on a manual that covers those adjustments for your car. My gut is something is adjusted incorrectly, which is the source of your problem. Reconditioned part are, by and large, fine. Did you bench bleed the master cylinder, prior to installation?

[TxGreaseMonkey]

An excellent product to have on hand is Motorcraft Silicone Brake Caliper Grease and Dielectric Compound (XG-3-A). It's available at your local Ford or Lincoln/Mercury dealer. It's amazing the number of applications this product can be used for; e.g. lubricating O-rings, rubber gaskets, disk brake caliper pins, plus using it as a dielectric compound for weatherizing battery and starter terminals and cables, fuse contacts, main grounds, main ECM ground, ECM connectors, ignitors, coils, spark plug connectors, coating spark plug porcelein, and tail and brake lights.

[parttime]

Hi frankie, one hidden cause of brake drag is deterioration in the rubber brake line, caused by letting the old caliber hang on by the hose. Have you changed them?

[frankiedon53]

Yes, I changed the front ones only, not the single rear one, and I was saying to my wife tonight that I should have changed that one too.I don't know if the rear hose would have any effect on the front.Today I bled the rear brakes again and the fluid that came out was black like rubber so it really gave me something to think about.As soon as I can I will get one.Don't you think that I should have it pressure bled in a shop or is it something that can be fixed with pedal bleeding .I find that there's an aweful lot of air bubbles when I pedal bleed and they never seem to want to stop coming.Thanks for the info. On the grease I'll get some soon.

[frankiedon53]

Oh, by the way I do have a manual but since I started going on line with this problem I don't read it quite as often.I have a haynes and a chilton manuals.You mean the adjustments on the brake pedal I think.I checked it and its OK it's not holding the pedal off.

[frankiedon53]

Tx.greasemonkey: I looked back at our discussion to see if you suggested anywhere that it is correct to lubricate the rubber seals in the master and calipers with the silicone grease.I know that one has to be very careful of what is used in the system like patroleum products is a definite no-no. thank you.

[TxGreaseMonkey]

Only use brake fluid to lubricate seals inside the master cylinder, calipers, and wheel cylinders.

[frankiedon53]

Txgreasemonkey: I'm onto a new idea about my problem and thought I would hear what you have to say.I recently learned that there was once a spate of defective master cylinders on the market and they were causing brake lock-up because of residual pressure problems and the return springs too strong.Although my van does"nt have that brand name I made me think that the reconditioned master cylinder I got may be faulty.So I dismantled it and compared the parts to the original master that I took off.Luckily I did not do a core return this time.I noticed that the parts in the recon.unit are very different from the original... The problem that I have now is : I had removed one of the rubber cups from the secondary piston and I felt that I reinstalled it correctly,[with both the lips facing the same direction] but the recon.unit has the lips facing opposite directions so,now I'm wondering which one is correct.What I want to do is put back in the pistons from the original master cyl.and see if the problem changes.If I had'nt remove that rubber it won't be a problem.I'm sure you would know which way is the correct way and I thank you for your help.The diagrams in the manual don't show close-ups of this. Thanks .

[TxGreaseMonkey]

I really hate to say, from afar. See if there's another master cylinder you can compare it to. My gut is they should face the same way, one for each brake circuit.

[frankiedon53]

Hi , don't forget that the primary piston is for the front brake the secondary piston is for the rear brake.But the question is if both rubbers on the secondary piston is suppose to face the same way or opposite ways.If they are suppose to face the same way then the recon. Unit was put together wrong.And I went with installing them the opposite way assuming that it was right and I was wrong .The brakes are holding good I suppose it's OK.But if I find out different later I'll just have to take it apart again.I'm getting better and better at it all the time.laugh! As far as the dragging goes I did not accomplish any thing by switching the pistons.I'm becoming convinced that maybe that's the way they are suppose to operate.Im going to drive the van some more and see what happens this time. Thanks again for your interest and time.